Antisense Downregulation of SPS in Arabidopsis Thaliana

Abstract

Sucrose-phosphate synthase (SPS) is the major regulatory enzyme in sucrose biosynthesis catalyzing the synthesis of sucrose from Fru6P and UDPG1u. There are two distinct mechanisms to control the enzymatic activity of the SPS protein: allosteric control by Glu6P and Pi, and covalent modification by protein phosphorylation¹. The amount of SPS transcript has also been reported to respond positively to glucose feeding². At low temperatures Arabidopsis has been shown to increase SPS activity and the amount of transcript for SPS³. Further, the flux of carbon into sucrose also increases after growth at low temperatures indicating an important role for SPS in cold acclimation. Our aim is to elucidate the role of SPS in the cold acclimation process. Arabidopsis plants with SPS downregulated using antisense technique were constructed to test the performance at low temperatures, although data is only presented in this report from warm temperature grown plants.